Genotype-by-environment interactions at the trait level and total merit index level for milk production and functional traits in Brown Swiss cattle

The production environments of the German-Austrian Brown Swiss population show a wide range due to differences in topography, landscapes, local climates, and different farm management systems. Extensive production systems such as organic farming have become increasingly popular in recent decades because of interest in sustainability and consumer preferences. Compared with conventional farmers, organic farmers put more weight on fitness traits. Besides the official total merit index (TMI), a selection index applying relative economic weights (REWs) suitable for organic production systems is provided for Brown Swiss cattle in Germany. The aim of the study was to investigate genotype-by-environment interactions (GxE) for milk production traits and functional traits (including longevity, fertility traits, and calving traits) in a sample of the German-Austrian Brown Swiss population housed in Baden-Wuerttemberg (southern Germany) by applying bivariate and random regression sire models. For bivariate analyses, the production environment was binary classified by farm management system (organic and conventional) and altitude of farm location (above or below 800 m above sea level (ASL)). Milk energy yields (MEY) obtained from herd effects were used as continuously scaled environmental descriptor in the reaction norm approach. The TMIs for sires were calculated based on breeding values estimated with different models and environment-specific REWs to determine possible GxE at TMI levels and rerankings of sires. In bivariate analyses, genetic correlations at the trait level were high and ranged from r_g = 0.99 (calving to first insemination, cystic ovaries, and maternal stillbirth rate) to r_g = 0.79 (first insemination to conception for altitude). Except for the latter, no severe GxE were found at the trait level using the bivariate models. Fat yield was the only trait showing minor GxE in the reaction norm model approach. Investigating the environmental sensitivity at the TMI level revealed rank correlations between the different environment-specific TMIs that were close to unity, implying no severe reranking effects. The results show no need to account for different environments in Brown Swiss cattle breeding programs.

Genomic analysis of perinatal sucking reflex in German Brown Swiss calves

A healthy sucking reflex is essential for newborn calves to ensure sufficient colostrum intake in the first few hours postpartum. In recent decades, European Brown Swiss breeders have repeatedly reported that some calves lack the ability to consume colostrum directly after birth due to an absent sucking reflex. In this study, we collected the phenotypes of more than 5,500 German Brown Swiss calves and performed variance component estimation with sire threshold models using Markov chain Monte Carlo algorithms. The 50K (777K) genotypes of nearly 2,000 (200) calves were collected, and an imputation was performed for all 50K genotypes up to 777K. Genome-wide association studies (GWAS) for the trait sucking reflex were conducted for all 777K genotypes. Depending on the trait coding, a low heritability was estimated to range from 0.08 to 0.11. The GWAS results identified 34 trait-associated SNP on 6 different chromosomes. Post-GWAS analyses showed significant overrepresentation of Gene Ontologies for central nervous development and several regulative processes. Functional annotation clustering and pathway analysis revealed relations to lipid metabolism, immune and endocrine systems, and signal transduction. The results of this study suggest that breeding for an improved sucking reflex is possible but requires large data sets for the estimation of reliable breeding values (either large progeny testing groups or a large reference genome in a genomic selection program).

Parsimonious model for analyzing parent-of-origin effects related to beef traits in dual-purpose Simmental

Genomic imprinting occurs when allelic effects depend on their parental origin. These parent-of-origin effects (POE) occur because of epigenetic DNA modifications during gametogenesis according to the sex of an animal. Animal breeding programs give little consideration to imprinting, although its relationship to important traits has been shown in different agricultural species. To incorporate imprinting, a previously proposed model (imprinting model) contains the genetic effects of the sire and dam, and it provides an estimate of the variance component due to POE, which is referred to as imprinting variance. Large volumes of data are sometimes available for commercial populations, so the dimension of mixed-model equations can become very large or even excessively large when estimating imprinting variances and other genetic parameters. To address this issue, we replaced the genetic effect as dam with the effect of the maternal grandsire in the imprinting model. When combined with appropriate weightings of the observations, this replacement yields an imprinting model with a parsimonious number of genetic effects for male parents and ancestors of slaughter animals, and it enables the inclusion of large volumes of data. In addition, we derived an equivalent model to facilitate the direct estimation of POE and their prediction error variances. We applied the parsimonious model to 1,366,160 fattening bulls as well as a pedigree of 2,637,761 ancestors to investigate the relevance of POE for beef performance in dual-purpose Simmental. We analyzed the killing-out percentage, net BW gain, carcass muscularity, and fat score as slaughter traits. The parsimonious model was applied as both linear and generalized linear versions with a logit-link function. The proportions of the total genetic variance attributable to POE ranged between 8.6% and 17.1%. For 3 of the 4 traits, the maternal gamete accounted for a greater proportion of the imprinting variance. The effects of POE and their reliabilities were estimated for up to 27,567 bulls and all traits, where the reliabilities ranged between 0.38 and 0.99. Thus, our new parsimonious model is appropriate for estimating the imprinting variance using large pedigree data sets. Our results highlight the need to consider POE in genetic evaluations.

Short communication: Importance of introgression for milk traits in the German Vorderwald and Hinterwald cattle

The subject of the present study was to analyze the influence of genetic introgression on milk yield performance of the German local Vorderwald and Hinterwald cattle breeds. Deviations of milk yield, fat yield, and protein yield of cows as well as pedigree information were analyzed. A sire model was used to estimate genetic trend and effects of the migrant breeds. Migrant contributions to Vorderwald cattle were high and have been rising even in the recent past. The effects of these breeds on milk yield performance were positive. Montbéliarde cattle not only had the largest effect on milk production of Vorderwald cattle but also the highest genetic contribution to this breed. Genetic introgression with Montbéliarde continued until recently. This suggests that introgression of high-yielding breeds is still a preferred method for genetic improvement of local breeds, even though it diminishes their value for conservation. Hence, the current population management has too little focus on the preservation of genetic uniqueness. In comparison, migrant breed contributions to the Hinterwald cattle, a breed with a unique phenotype and an own niche, were moderate and almost constant over the time. For the Hinterwald cattle, no significant effect of migrant breeds could be detected, which suggests that population management has different priorities in different endangered breeds. We conclude that not only the registration of animals from local breeds but also the breeding programs themselves should be supported and need to be controlled.

The contribution of migrant breeds to the genetic gain of beef traits of German Vorderwald and Hinterwald cattle

During the past decades, migrant contributions have accumulated in many local breeds. Cross-breeding was carried out to mitigate the risk of inbreeding depression and to improve the performance of local breeds. However, breeding activities for local breeds were not as intensive and target oriented as for popular high-yielding breeds. Therefore, even if performance improved, the gap between the performance of local and popular breeds increased for many traits. Furthermore, the genetic originality of local breeds declined due to the increasing contributions of migrant breeds. This study examined the importance of migrant breed influences for the realization of breeding progress of beef traits of German Vorderwald and Hinterwald cattle. The results show that there is a high amount of migrant contributions and their effects on performance are substantial for most traits. The effect of the French cattle breed Montbéliard (p-value 0.014) on daily gain of Vorderwald bulls at test station was positive. The effects of Vorderwald ancestors (p-value for daily gain 0.007 and p-value for net gain 0.004) were positive for both traits under consideration in the population of Hinterwald cattle. Additionally, the effect of remaining breeds (p-value 0.030) on net gain of Hinterwald cattle in the field was also positive. The estimated effect of Fleckvieh ancestors on net gain of Hinterwald cattle was even larger but not significant. Breeding values adjusted for the effects of the migrant breeds showed little genetic trend.

Evaluation of prolactin receptor (PRLR) as candidate gene for male fertility in Hanoverian warmblood horses

Stallion fertility has increasing importance as the artificial insemination is employed in horses more intensely. Molecular genetic markers may be useful tools to evaluate the stallion fertility before breeding. The prolactin receptor gene (PRLR) was chosen as a candidate for stallion fertility because of its influence on testicular and accessory sex gland function. Screening the equine PRLR gene for polymorphisms in Hanoverian stallions revealed two single nucleotide polymorphisms (SNPs). Association and haplotype analyses were performed in 162 Hanoverian warmblood stallions for these intragenic SNPs using the least square means (LSM) of the pregnancy rate per oestrus for stallions and the paternal component and embryonic component of the breeding values (BV) of the pregnancy rate per oestrus. The two SNPs (BIEC2-589441, BIEC2-560860) showed significant associations using single marker and haplotype analysis with the embryonic and paternal component of BV and one SNP (BIEC2-560860) was also significantly associated with the LSM of the pregnancy rate per oestrus. This is the first report on an association of PRLR-associated genetic markers with fertility traits in stallions.

INHBA-associated markers as candidates for stallion fertility

The inhibin beta A (INHBA) gene was chosen as candidate for stallion fertility and analysed for intragenic markers to find associations with pregnancy rate per oestrus. Intragenic single nucleotide polymorphisms (SNPs) were developed in order to perform an association and haplotype analysis using the least square means (LSM) of the pregnancy rate per oestrus for stallions as well as breeding values (BVs) for the embryonic and paternal component of the pregnancy rate per oestrus. The polymorphisms were genotyped in 161 Hanoverian warmblood stallions. Insemination records from approximately 20,000 Hanoverian warmblood mares were used to calculate LSM for stallions and to predict the paternal and embryonic component of BVs for the pregnancy rate per oestrus. We demonstrated significant associations of single markers and haplotypes with the LSM and the embryonic and paternal component of BVs for the pregnancy rate per oestrus. This is the first report on INHBA as an associated candidate gene with the LSM of stallions and the paternal and embryonic component of BVs for the pregnancy rate per oestrus.

Effect of polymorphisms in four candidate genes for fertility on litter size in a German pig line

We carried out an SNP discovery project in pigs for candidate genes playing potentially important roles in embryonic development. Using eight pigs one each from eight breeds (Meishan, Mangalitza, Duroc, Pietrain, German Landrace, Hampshire, Husum Red Pied, German Large White), 36 SNPs were identified in intronic sequences of 21 porcine candidate genes based on sequencing of PCR products. The primer pairs were designed using porcine EST sequences allowing amplification of introns. These SNPs were tested for their association with the number of piglets born alive in German Large White sows using a discordant approach. Significant effects (p < 0.001 and p < 0.05, respectively) of intronic SNPs on litter size were found for four genes: mitogen-activated protein kinase kinase kinase 3 (MAP3K3), vascular endothelial growth factor receptor (KDR), erbb2 interacting protein (ERBB2IP) and peroxisome proliferator-activated receptor delta (PPARD). These SNPs can be further tested in upcoming association studies for their influence on litter size in different breeds using larger sample sizes.

Evaluation of bone strength, keel bone deformity and egg quality of laying hens housed in small group housing systems and furnished cages in comparison to an aviary housing system

Abstract. The objective of the study was to assess bone breaking strength, keel bone status and egg quality parameters of Lohmann Silver (LS) and Lohmann Tradition (LT) layers housed in small group systems (SG) and furnished cages (FC) in comparison to an aviary system. At the end of the 3rd, 6th, 9th and 11th laying month, approximately 40 hens were randomly chosen from each housing system and slaughtered (478 hens in total). Humerus and tibia strengths were analysed using a three-point-bending machine. Keel bone status was evaluated on a scale from 1 (severe) to 4 (no deformity). Shell breaking strength was measured every four weeks, totalling 4,887 eggs. Statistical analyses were performed using the MIXED procedure of SAS. Humerus and tibia strengths of LS layers housed in SG were significantly higher compared to LS hens kept in FC. Bone breaking strengths of humerus and tibia in LS and LT layers were highest in the aviary system and the differences to the other housing systems were significant. No significant differences in tibia and humerus bone breaking strengths were found between SG and FC for LT hens. Keel bone status was not significantly influenced by housing system or laying strain. For both hybrids, shell breaking strength was significantly lower in SG compared to FC and aviary system. The results showed that SG systems can significantly enhance bone breaking strength for LS layers in comparison to hens kept in FC. The lower shell breaking strength of eggs in SG might slightly impair economic aspects.

Effect of polymorphisms in the genes for LIF and RBP4 on litter size in two German pig lines

The association of two diallelic polymorphisms in the porcine genes for leukaemia inhibitory factor (LIF) and retinol-binding protein 4 (RBP4) with number of piglets born alive (NBA) in two German pig lines was studied. The investigated single nucleotide polymorphism (SNP) in the porcine LIF gene has been located in the 3'-untranslated region of its third exon, whereas the SNP in the RBP4 gene genotyped in this study is intronic. At the LIF locus the allele frequencies were 0.613 for the A allele and 0.387 for the B allele in German Landrace (GL) and 0.276 for A and 0.724 for B in German Large White (GW). At the RBP4 locus, the allele frequencies were 0.586 for the A allele and 0.414 for the B allele in GL and 0.733 for A and 0.267 for B in GW. There was a significant additive effect of the LIF B allele on NBA in GW over all parities (p <or= 0.05) and a significant positive dominance effect of 0.69 +/- 0.22 (p = 0.002) was observed for first parity on NBA in GL. For RBP4, no association of genotypes and NBA was detected in GW but a significant additive effect of the A allele of 0.24 +/- 0.11 (p = 0.027) and a significant dominance effect of 0.31 +/- 0.13 (p = 0.020) were found in GL over all parities and confirmed through the evaluations by parity.

Genetic variability in Hanoverian warmblood horses using pedigree analysis

A data set constituting a total of 310,109 Hanoverian warmblood horses was analyzed to ascertain the genetic variability, coefficients of inbreeding, and gene contributions of foreign populations. The reference population contained all Hanoverian horses born from 1980 to 2000. In addition, Hanoverian stallions born from 1980 to 1995 and Hanoverian breeding mares from the birth years 1980 to 1995 with registered foals were analyzed for the same genetic parameters. The average complete generation equivalent was approximately 8.43 for the reference population. The mean coefficient of inbreeding was 1.33, 1.19, and 1.29% for the reference population, stallions, and breeding mares, respectively. The effective number of founders was largest in stallions (364.3) and smallest in the reference population (244.9). The ratio between the effective number of founders and the effective number of ancestors was 3.15 for the reference population, 3.25 for the stallions, and 3.06 for the breeding mares. The effective population size in the Hanoverian warmblood reference population was 372.34. English Thoroughbreds contributed nearly 35% of the genes to the Hanoverian reference population and even slightly greater contributions (39%) to the stallions. Trakehner and Arab horses contributed approximately 8 and 2.7%, respectively, to the Hanoverian gene pool. The most important male ancestors were Aldermann I from the A/E line, Fling from the F/W line, and Absatz from the Trakehner line, whereas the breeding mare Costane had the greatest contribution to the reference population, stallions, and breeding mares. From 1996 onward, the stallions Weltmeyer and Donnerhall had the largest genetic impact on the Hanoverian horse population.

Evidence of a new leukemia inhibitory factor-associated genetic marker for litter size in a synthetic pig line

The association of a diallelic polymorphism in the leukemia inhibitory factor (LIF) gene with reproductive, growth, and carcass traits was studied in a German synthetic pig line. The diallelic SNP has been located in the 3'-untranslated region of the third exon of the porcine LIF gene. Information on 955 litter records from 273 genotyped sows was used in the analyses with respect to the number of piglets born alive. To identify possible pleiotropic marker effects, the growth and carcass traits ADG and backfat thickness were tested for associations with the SNP within the LIF gene in this population. At the LIF locus, the allele frequencies were 0.27 for the A allele and 0.73 for the B allele. There was an indication of an additive effect on the number of piglets born alive, and a significant dominance effect of the B allele was observed for first, second, and third to 10th parities (P = 0.044). The dominance effect for the first parity amounted to -0.73 +/- 0.36 (P = 0.047). No associations were detected between the marker alleles and the growth and carcass traits.

Phylogenetic relationships of German heavy draught horse breeds inferred from mitochondrial DNA D-loop variation

We analysed a 610-bp mitochondrial (mt)DNA D-loop fragment in a sample of German draught horse breeds and compared the polymorphic sites with sequences from Arabian, Hanoverian, Exmoor, Icelandic, Sorraia and Przewalski's Horses as well as with Suffolk, Shire and Belgian horses. In a total of 65 horses, 70 polymorphic sites representing 47 haplotypes were observed. The average percentage of polymorphic sites was 11.5% for the mtDNA fragment analysed. In the nine different draught horse breeds including South German, Mecklenburg, Saxon Thuringa coldblood, Rhenisch German, Schleswig Draught Horse, Black Forest Horse, Shire, Suffolk and Belgian, 61 polymorphic sites and 24 haplotypes were found. The phylogenetic analysis failed to show monophyletic groups for the draught horses. The analysis indicated that the draught horse populations investigated consist of diverse genetic groups with respect to their maternal lineage.

Foot pad health, plumage condition, integument and claw length of Lohmann Silver laying hens kept in small aviary housing systems, furnished cages and an aviary housing system

Abstract. In the 3rd, 6th, 9th and 12th laying month, foot pad health, plumage condition, integument and claw length were evaluated in 432 Lohmann Silver laying hens kept in three different housing systems: a small aviary housing system (Eurovent 625a-EU, EV) with different perch levels, a furnished cage system (Aviplus, AP) and an aviary (Voliere Natura, AV). Foot health was scored for hyperkeratosis and lesions on a scale from 1 (normal) to 5 or 4 (severe). Plumage condition was assessed with scores from 1 (worst) to 4 (best) for different body regions. Integument was assessed for lesions and claw length of the middle toe was measured. Mild foot pad hyperkeratosis was the most frequent finding in hens of all housing systems. Sole pad hyperkeratosis was less frequent in AP and occurred more often in EV and AV. Significantly more often hyperkeratosis in the region between toe and claw was observed in AP. Toe pad lesions and lesions between toe and claw were scored lowest in AV and highest in AP. An aggravation of plumage in the course of the laying period was observed in all hens. Hens showed a significantly better total plumage condition in AP compared to EV. Within housing system, group size had a significant influence on plumage condition. Plumage was better in smaller groups. Lesions of the integument were rarely detected. Claws were significantly shortest in AP, longer in AV and longest in EV. Perch design in EV was not significant for all traits except for comp lesions.

Genetic parameters for the prevalence of osteochondrosis in the limb joints of South German Coldblood horses

Heritabilities were estimated for osteochondrosis (OC) in fetlock and hock joints and palmar/plantar osseous fragments in fetlock joints of South German Coldblood (SGC) horses using Residual Maximum Likelihood (REML) under a linear animal model. The analyses were based on the results of a standardized radiographic examination of 167 SGC horses with a mean age of 14 months. The heritabilities linearly estimated and transformed onto the liability scale were for OC in fetlock joints 0.16 and for OC in hock joints 0.04. Considering fetlock and hock OC together, results in a heritability of 0.17. Palmar/plantar osseus fragments of the fetlock joints showed a heritability of 0.48. We concluded that there is most likely a genetic component in the variation of the development of osteochondrosis in fetlock and hock joints as well as for palmar/plantar osseus fragments of fetlock joints of the investigated population of SGC horses.

Analysis of the Canine mdr1?1? Mutation in the Dog Breed Elo

A deletion mutation in the canine multidrug resistance gene, MDR1, is associated with drug sensitivity. This was shown for several purebred dog breeds from the Collie lineage such as the Collie (rough-coated and smooth-coated), the Australian Shepherd and the Old English sheepdog. To determine whether the mdr1-1Delta mutation could be found in the newly bred German dog breed Elo which is based amongst other breeds on Old English sheepdogs, 177 blood samples representative for the Elo breed were collected. After DNA extraction, a polymerase chain reaction-based method with subsequent polyacrylamide gel electrophoresis was used for detection of the mdr1-1Delta mutation. The mdr1-1Delta allele was not observed in the Elos investigated. The probability that the mdr1-1Delta allele originated in the Old English sheepdog breed is segregating in the Elo population was estimated at 3.68 x 10(-17).

Mapping quantitative trait loci for osteochondrosis in fetlock and hock joints and palmar/plantar osseus fragments in fetlock joints of South German Coldblood horses

The aim of this study was to identify quantitative trait loci (QTL) for osteochondrosis (OC) and palmar/plantar osseous fragments (POF) in fetlock joints in a whole-genome scan of 219 South German Coldblood horses. Symptoms of OC and POF were checked by radiography in 117 South German Coldblood horses at a mean age of 17 months. The radiographic examination comprised the fetlock and hock joints of all limbs. The genome scan included 157 polymorphic microsatellite markers. All microsatellite markers were equally spaced over the 31 autosomes and the X chromosome, with an average distance of 17.7 cM and a mean polymorphism information content (PIC) of 63%. Sixteen chromosomes harbouring putative QTL regions were further investigated by genotyping the animals with 93 additional markers. QTL that had chromosome-wide significance by non-parametric Z-means and LOD scores were found on 10 chromosomes. This included seven QTL for fetlock OC and one QTL on ECA18 associated with hock OC and fetlock OC. Significant QTL for POF in fetlock joints were located on equine chromosomes 1, 4, 8, 12 and 18. This genome scan is an important step towards the identification of genes responsible for OC in horses.

Complex segregation analysis of dilated cardiomyopathy (DCM) in Irish wolfhounds

The objective of the present study was to analyse the mode of inheritance for dilated cardiomyopathy (DCM) in Irish wolfhounds using regressive logistic models by testing for mechanisms of genetic transmission. Insights from this spontaneous animal model should aid importantly in understanding basic pathogenic mechanisms with regard to genetics and molecular biology of DCM in humans. Moreover, a procedure for the simultaneous prediction of breeding values and the estimation of genotype probabilities for DCM is expected to markedly improve breeding programmes. Results of cardiovascular examinations of 1018 dogs carried out between 1987 and 2003 by one veterinarian were analysed. Data of 878 dogs from 531 litters in 147 different kennels were used for complex segregation analyses. Pedigree information was available for more than 15 generations. Male dogs were affected significantly more often by DCM than female dogs. The segregation analysis showed that among all other tested models a mixed monogenic-polygenic model including a sex-dependent allele effect best explained the segregation of affected animals in the pedigrees. A pure monogenic inheritance of DCM could be significantly rejected in favour of the major gene and most general model. The gene action of the major gene was significantly different between female and male dogs.

A polymorphism within the equine CRISP3 gene is associated with stallion fertility in Hanoverian warmblood horses

Fertility of stallions is of high economic importance, especially for large breeding organisations and studs. Breeding schemes with respect to fertility traits and selection of stallions at an early stage may be improved by including molecular genetic markers associated with traits. The genes coding for equine cysteine-rich secretory proteins (CRISPs) are promising candidate genes because previous studies have shown that CRISPs play a role in the fertilising ability of male animals. We have previously characterised the three equine CRISP genes and identified a non-synonymous polymorphism in the CRISP1 gene. In this study, we report one non-synonymous polymorphism in the CRISP2 gene and four non-synonymous polymorphisms in the CRISP3 gene. All six CRISP polymorphisms were genotyped in 107 Hanoverian breeding stallions. Insemination records of stallions were used to analyse the association between CRISP polymorphisms and fertility traits. Three statistical models were used to evaluate the influence of single mutations, genotypes and haplotypes of the polymorphisms. The CRISP3 AJ459965:c.+622G>A SNP leading to the amino acid substitution E208K was significantly associated with the fertility of stallions. Stallions heterozygous for the CRISP3 c.+622G>A SNP had lower fertility than homozygous stallions (P = 0.0234). The pregnancy rate per cycle in these stallions was estimated to be approximately 7% lower than in stallions homozygous at this position.

Macroscopic and histopathological alterations of foot pads of laying hens kept in small group housing systems and furnished cages

1. Foot pad health was determined macroscopically and histologically in two trials with Lohmann Selected Leghorn (LSL, white layer strain) and Lohmann Brown (LB) laying hens kept in a small group housing system (40 and 60 hens) and two types of furnished cages (10 and 20 hens). 2. A total of 864 foot pads (648 LSL and 216 LB) were examined macroscopically and classified according to severity of pathological alterations; of these, 180 metatarsal pads and 180 toe pads were also examined histologically for hyperkeratosis, acanthosis, elongation of rete folds, development of secondary papillae, erosion, ulceration, cellular infiltration and bacterial colonisation of the epidermal surface. 3. As for the macroscopic examinations, pathological alterations of foot pads were found in 86.1% of the hens, while 57.4% of the birds examined showed mild hyperkeratosis. Macroscopically moderate hyperkeratosis and/or superficial lesions of the epithelium were detected in 21% of the laying hens examined. Severe hyperkeratosis and/or deep epithelial lesions and/or mild swelling of the foot pads were found in 5.9% of the hens, and very severe hyperkeratosis and/or deep and large epithelial lesions and/or moderate or high-grade swelling of foot pads were found in 1.9%. 4. The histopathological examinations showed that the macroscopically determined thickening of the epidermis was due not only to hyperkeratosis, but also often to acanthosis. In addition, perivascular infiltrations of lymphocytes were also detected. Furthermore, the degree of hyperkeratosis in metatarsal pads was shown to correlate with the other histopathological traits except for ulceration, and the degree of hyperkeratosis in toe pads was related to the development of secondary papillae and cellular infiltration with lymphocytes. 5. The results of the macroscopic and histological examinations showed that the use of perches and the grasping of wire floor may have resulted in a permanent increased mechanical compression load leading to proliferative hyperkeratosis.

Prevalence of Osteochondrosis in the Limb Joints of South German Coldblood Horses

This study aimed to quantify the factors associated with the prevalence of the radiological signs of osteochondrosis (OC) and osteochondrosis dissecans (OCD) in South German Coldblood (SGC) horses. The prevalence of OC and OCD in fetlock and hock joints was analysed in 167 young coldblood horses with a mean age of 14 months. The presence of at least one osteochondrotic lesion (OC) in fetlock or hock joints was documented for 61.7% of the horses and 26.9% of the horses had osseus fragments. Osteochondrotic findings at the dorsal aspect of the sagittal ridge of the third metacarpal/metatarsal bone were seen in 53.9% of the horses and palmar/plantar osseous fragments in fetlock joints in 16.2% of the horses. Hock joint OC was found in 40.1% of the horses and hock OCD in 0.6%. Osteochondrotic findings in the distal part of the tibia were prevalent in 28.1% and in the lateral trochlea tali in 17.4% of the horses. The sex of the investigated horses significantly influenced the prevalence of OC in fetlock and hock joints, as well as the findings in the distal part of the tibia and lateral trochlea tali. Age at radiological examination was significant for the prevalence of OC in hock joints, palmar/plantar osseous fragments in fetlock joints and osteochondrotic findings in the distal part of the tibia. Female horses showed a 2-fold higher risk for OC in fetlock and hock joints than male horses. The distribution of the affected horses by age classes showed that radiographic signs of OC in fetlock and hock joints significantly increased at an age of about 1 year. We can conclude from our study that fetlock and hock OC is a prevalent radiographic finding in more than 1-year-old female and male SGC horses.

Analyse von Gesundheitsmerkmalen in verschiedenen Prüfabschnitten des Nachkommentests auf Station bei Deutschen Fleckviehbullen

Abstract. Title of the paper: Analysis of health traits in different lifetime classes in stationary progeny tested German Fleckvieh bulls The objective of this study was to analyse systematic environmental and genetic effects on the incidence and number of treatments due to bronchopneumonia and other diseases for five different age groups in German Fleckvieh bulls. The data set contained 1775 male calves kept under identical housing and management conditions from the age of about 25–50 days to 450 days for a stationary progeny test in growth and carcass traits. The age groups distinguished were from day 10–75 (1), 76–100 (2), 101–150 (3), 151–200 (4) and > 200 (5) of age. Fixed environmental effects tested for significance in generalized or general linear models were barn at entry, age at entry, region of origin, season of entry, diagnosis of bronchopneumonia at entry, test group within year of entry and weight at entry. Heritabilities were estimated in linear multivariate animal models using Residual Maximum Likelihood (REML). The multivariately estimated heritabilities for the incidence of bronchopneumonia were between h2 = 0.22 (first age group) and h2 = 0.07 (fourth age group). The DEMPSTER and LERNER (1950) transformation resulted in estimates of h2 = 0.34 for the first and h2 = 0.13 for the fourth age group. The additive genetic correlations varied from rg = −0.76 (2nd–5th age group) to rg = 0.78 (1st–3rd age group). The lowest value of the residual correlation was re= −0.05 (1st–4th age group) and the highest value was re = 0.16 (4th–5th age group). The multivariately estimated heritabilities for the number of treatments due to bronchopneumonia were highest in the first age group with h2 = 0.29 and lowest in the fourth age group with h2 = 0.08. The additive genetic correlations ranged between rg = 0.64 (1st –3rd age group) and rg = −0.33 (2nd–5th age group). The residual correlations were between re = −0.11 (1st–3rd age group) and re = 0.33 (4th–5th age group). Genetic differences among animals in resistance to bronchopneumonia are expressed most clearly in the lifetime period between day 40 and 150.

Evaluierung von Kleingruppenhaltungssystemen und ausgestalteten Käfigen hinsichtlich Brustbeindeformationen, Gefiederstatus, Krallenlänge und Körpermasse bei den Legelinien Lohmann Selected Leghorn und Lohmann Brown

Abstract. Title of the paper: Evaluation of small group housing systems and furnished cages concerning keel bone deformities, plumage condition, claw length und body weight in layer strains Lohmann Selected Leghorn and Lohmann Brown Small group housing systems (Eurovent 625+a-EU) and furnished cages (Aviplus und Eurovent 625A-EU) were evaluated for the occurrence of keel bone deformities, plumage condition, claw length and body weight. The examinations were performed in two layer strains, Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB), over two laying periods. In addition, the effects of layer strain, month of laying period, rearing method, group- size and body weight on these traits were tested. The assessments based on a scoring system comprising the scores 1 (very severely defective part of the body) to 4 (intact part of the body) were performed every three months during the laying period. Examinations of keel bone condition and measurements of body weight were performed in a total of 864 hens, claw length and plumage condition were examined in a total of 720 hens. Housing system showed a significant effect on the incidence of keel bone deformities and claw length. Plumage condition was significantly affected by group size, whereas plumage condition was worst in groups of 20 hens in Aviplus and in groups of 10 hens in Eurovent 625A-EU. Concerning claw length there were significant differences between diverse claw abrasives. The strongest abrasion was found in groups with two abrasive blocks, whereas perforated metal plates led to the least abrasion. Month of laying period showed a significant effect on each examined trait with a decrease in keel bone and plumage condition and an increase in claw length and body weight during the laying period.

Keeping laying hens in furnished cages and an aviary housing system enhances their bone stability

1. Tibia and humerus breaking strength of Lohmann Silver hybrids kept in conventional cages, furnished cages and an aviary with outdoor run were examined in two production cycles. Each trial lasted a full laying period; feeding, management and healthcare were identical for all hens. In both trials bone strength was investigated at the end of laying months 6, 9 and 14. 2. The objective was to determine if bone strength increases when hens are kept in alternative housing systems, especially in furnished cages, and whether hen age affects bone stability. 3. The results indicated that housing system influenced bone breaking strength, which was consistently higher for hens in the aviary compared to hens in conventional and furnished cages. Furthermore, humerus breaking strength was higher for hens in furnished cages compared to conventional cages. No significant difference regarding tibia breaking strength was found between conventional and furnished cages. 4. Our results showed that lack of exercise contributed to the problem of weak bones more than did calcium depletion from eggshell formation. 5. Tibia breaking strength increased during the last third of the production cycle, whereas humerus breaking strength remained unaffected by hen age. 6. Genetic group affected only tibial bone breaking strength, which was lower overall in genetic group A than in group B, which in turn was lower than group C. 7. The increased bone strength in the aviary and in the furnished cages probably reduced the incidence of recently broken bones in these systems compared to the conventional cages. This increase in bone strength can be regarded as an improvement in welfare. Furnished cages, like the aviary system, might be considered an alternative housing system for laying hens, because both resulted in enhanced bone strength.

Associations between prion protein genotype and type traits in East Friesian milk sheep

Linear models were used to analyse the relationships between the prion protein genotypes and the height at the withers and rump, the heart girth and the length of the trunk of 440 East Friesian milk sheep. Significant associations were found between the ARR allele and the height of the withers and rump, and heart girth. The average height at the withers of the homozygous ARR/ARR sheep was 1.9 cm less than that of ARQ/ARQ sheep and 1.6 cm less than in sheep heterozygous for ARR; the height at the rump, length of the trunk and heart girth were similarly smaller. In the ARR/ARR ewes, the average height at the withers was 2.6 cm less and the height at the rump was 1.9 cm less than in the ARQ/ARQ ewes.

[Genetic influences on the outcome of the progeny tests for behaviour traits in Hovawart dogs]

The objective of the present study was to evaluate the importance of genetic and environmental sources of variation for results of behaviour tests in young dogs being used for progeny evaluations in the Hovawart dog. In total, 4,113 dogs born in 1995 to 2000 have been available for these analyses. Traits used were appearance, hunting affinity, group of people, acoustical and optical influences and temperament. Variance components were estimated using multivariat linear animal models and Restricted Maximum Likelihood (REML). The models included test-year-season, sex, litter size, age and inbreeding coefficient of the animal as fixed effects. Additive genetic effects of the animal, permanent environmental effect of the litter and the effect of the kennel were considered as random factors. The sex of the dog was significant for all traits. The age of the dog at the test significantly influenced the traits temperament and appearance. Test-year-season was significant for all traits except for appearance, whereas the inbreeding coefficient of the animal was significant for acoustical influences and temperament. Litter size did not influence any of the traits significantly. The estimated heritabilities of the behaviour traits analysed here ranged from h2 = 0.03 to h2 = 0.11 with standard errors of up to 0.03. The additive genetic correlations between most of the traits were moderately to highly positive (rg = 0.16 to rg = 0.91). The traits hunting affinity and appearance showed an additive genetic correlation close to zero (rg = 0.03). Negative additive genetic correlations were found between temperament and appearance as well as acoustical and optical influences (rg = -0.14 to rg = -0.4).

Genetic analysis of three different classification protocols for the evaluation of elbow dysplasia in German shepherd dogs

OBJECTIVES

Three different scoring systems for elbow dysplasia and its radiographic signs were genetically evaluated in 2645 German shepherd dogs.

METHODS

An animal model was used to estimate heritabilities and additive genetic and residual correlations for the three scoring systems: ED-SV, which is recommended by the International Elbow Working Group; ED-LA, developed by Lang and others; and ED-TH, proposed by Tellhelm.

RESULTS

The effects of sex, age at examination and the correlation between the two factors were significant for all three scoring systems. Heritability estimates (se) were 0.18 (0.04) for ED-SV, 0.11 (0.03) for ED-LA and 0.16 (0.04) for ED-TH. The additive genetic correlations among the different single criteria for elbow dysplasia and the different elbow dysplasia scores were between 0.68 and 0.98, except for the criteria ununited anconeal process and osteochondrosis dissecans of the trochlea humeri, which were mostly genetically negatively correlated to the other radiological criteria.

CLINICAL SIGNIFICANCE

The elbow dysplasia scores were determined by two genetically different traits. The possibilities for selecting German shepherd dogs with respect to elbow dysplasia might be improved by taking into account these two traits in the prediction of breeding values.

[Effects of different selection strategies on breeding towards scrapie resistance in the German Grey-horned Heath population]

Scrapie resistance is related to polymorphisms of the prion protein (PrP) gene. The homozygous ARR/ARR genotype of the prion protein gene is associated with high resistance against conventional scrapie infections. But this can lead to a distinct loss of genetic variation in breeds with a small population size or a low frequency of the ARR allele. For these populations an optimal breeding scheme for breeding towards scrapie resistance and an arbitrarily chosen production trait with conservation of the genetic diversity is not known yet. A simulation programme was developed, in which the structures of local populations could be used as input parameters, and the development of the ARR allele frequency, of the inbreeding coefficient, of a production trait and the genetic drift were computed in dependence of different selection schemes for scrapie resistance. An optimal strategy for the German Grey Heath population from Lower Saxony should be found. An optimal strategy in a breeding programme for ARR homozygosis should also maintain the genetic diversity present in a breed. This could be achieved when initially ARR heterozygous sheep were bred until a certain threshold value of the ARR allele was reached. The speed and costs of the breeding progress towards fixation of the ARR allele should then be optimized with regard to the aims of the breeders and breeding organisations, whereas a faster breeding towards scrapie resistance goes along with higher genotyping costs and vice versa.

Effect of furnished small group housing systems and furnished cages on mortality and causes of death in two layer strains

1. Mortality and causes of death were recorded over two trials with 13045 Lohmann Selected Leghorn (LSL, white layer strain) and 4410 Lohmann Brown (LB) laying hens kept in furnished small group housing systems and furnished cages. In trial 1, hens were housed from weeks 19 to 71 (LSL) and 17 to 69 (LB). In trial 2, LSL hens were housed from weeks 18 to 57. 2. The hens were kept in groups of 40 and 60 in the furnished small group housing system Eurovent 625 + a-EU and in groups of 10 and 20 in the furnished cages Aviplus and Eurovent 625A-EU. 3. To investigate the possible effect on mortality of rearing the birds on litter floors or in cages, in trial 2 half of the LSL hens were reared on the floor and half in conventional cages. 4. Mortality was greater in the Eurovent furnished small group housing system (5.2%) than in the furnished cages Aviplus (4.0%) and Eurovent (4.2%). 5. Mortality was also affected by the interactions among housing system and trial, layer strain and rearing. In trial 1, more LB laying hens died in the Aviplus system than in the Eurovent group system. There was no significant difference in mortality of the LSL laying hens between housing systems in trial 1. In trial 2, mortality of the LSL hens was greater in the group housing system (hens reared on litter floors: 10.1%; hens reared in cages: 2.8%) than in the furnished cage Aviplus (hens reared on litter floors: 6.0%; hens reared in cages: 1.5%). 6. Mortality was greater in floor-reared LSL laying hens than in the LSL laying hens reared in conventional cages. 7. Group size within housing system had no significant effect on mortality. 8. The most common findings at autopsy were different types of cannibalism (65.51%), with vent cannibalism (38.57%) the most common.

Production, egg quality, bone strength, claw length, and keel bone deformities of laying hens housed in furnished cages with different group sizes

The effects of 3 different furnished cage systems (Aviplus, Eurovent 625a, Eurovent 625A) on 2 different laying hen strains [Lohmann Selected Leghorn (LSL), Lohmann Brown (LB)] were examined for the traits of production, egg quality, bone strength, claw length, and keel bone status. Two trials were carried out in which all hens received identical feeding and management. In brown hens, the traits egg production per average hen housed, cracked eggs, feed conversion, egg weight, and humerus breaking strength were significantly higher than in white hens. Furthermore, the claws of the brown hens were shorter than those of white hens. There were more dirty eggs, higher shell density, and fewer keel bone deformities in white hens than in brown hens. In the Aviplus system, egg production per average hen housed was higher than in the other systems, whereas shell thickness and density were lower. Humerus strength was also higher in the Aviplus than in the Eurovent 625a system, whereas there was no significant difference in tibia strength among the 3 systems. The shortest claws were found in the Aviplus system, and the fewest keel bone deformities occurred in the Eurovent 625a system. The study showed that the high standards of conventional cages for production and egg quality were met in furnished cages and that bone strength was significantly greater than in conventional cages. Claw shortening devices in furnished cages seemed satisfactory, because claws were generally short. However, the occurrence of keel bone deformities due to the intensive use of perches seemed to be a problem of furnished cages.

Complex Segregation Analysis of Canine Hip Dysplasia in German Shepherd Dogs

Complex segregation analyses were carried out to clarify the mode of inheritance of canine hip dysplasia (CHD) in German shepherd dogs. Data were used from 8,567 animals examined for CHD from 20 families with three to four generations. The existence of a major gene in addition to polygenic gene effects was detected. In the present study, a mixed model with a dominant major gene effect seemed to be most probable for dichotomous encoding (0: dogs without signs of CHD; 1: dogs with borderline/slight to severe CHD). In addition, mixed major gene inheritance was shown for a binary trait where borderline was assigned to dogs scored free from CHD and for a trichotomously encoded trait (0: dogs without signs of CHD; 1: borderline CHD; 2: mild to severe CHD). Although only small frequencies were found for the unfavorable homozygotic genotype AA, the probability of the AB genotype was high in affected animals. Selection schemes to reduce the frequency of the allele A should therefore efficiently improve existing breeding programmes in German shepherd dogs.

Genetische Parameter für Fruchtbarkeitsmerkmale bei Landschafrassen

Abstract. Title of the paper: Genetic parameters for reproduction traits in land sheep breeds The objective of the study was a genetic statistical analysis of reproduction traits from 13164 lambings in German Grey Heath, 2260 in German White Heath, 12961 in German Polled Heath, 11258 in Bentheim and 3088 in Coburg. Reproduction traits included early lambing (≤ 550 days), late lambing (>550 days), first lambing interval, second lambing interval and total number of lambs born. Three different linear animal models were used for analysing of these traits. The heritabilities ranged from h² = 0.43 to 0.45 for the trait early lambing, between h2 = 0.11 and 0.40 for the trait late lambing, between h2 = 0.05 and 0.24 for the first lambing interval, between h2 = 0.02 and 0.20 for the second lambing interval and between h2 = 0.06 and 0.07 for the total number of lambs born. There were high additive genetic correlations between the first three parity numbers. Because of this, the parity numbers were analysed together using a repeatability model. Additive genetic correlations between early or late lambing and first lambing interval, early lambing and late lambing interval as well as between first and second lambing interval were moderate and negative.

Prevalence of Osseous Fragments in Distal and Proximal Interphalangeal, Metacarpo- and Metatarsophalangeal and Tarsocrural Joints of Hanoverian Warmblood Horses

The prevalence of osseous fragments in different limb joints was analysed in 3749 young Warmblood riding horses, which were pre-selected for sale at auction from 1991 to 1998 by the Association of Hanoverian Warmblood Breeders (Verband hannoverscher Warmblutzüchter e.V.) in Verden (Aller), Germany. The evaluation of these horses was based on a standardized radiological examination, including the distal interphalangeal (DIJ), the proximal interphalangeal (PIJ), the metacarpo- and metatarsophalangeal (MC/MTJ) and the tarsocrural joints (TCJ). In 32% of all horses at least one osseous fragment was found on these radiographs. TCJ were affected in 9.6% of the horses and MC/MTJ in 20.7%. The percentage of horses affected in the MTJ was significantly higher (13.7%) than that of horses affected in the MCJ (9.5%). The prevalences of osseous fragments were considerably lower in DIJ (4.5%) and PIJ (0.9%). Osseous fragments only occurred either in DIJ or PIJ or MC/MTJ or TCJ in 87% of the affected horses. Depending on the joint type, osseous fragments were found in analogous joints in the front and the hind limbs in up to 26% of the affected horses, whilst bilateral affection occurred in between 10% and 46% of the horses. Distribution of osseous fragments in the limb joints investigated here did not differ significantly between male and female horses. There was a significant increase in the percentage of horses with osseous fragments in MC/MTJ during the study period. The results of this study indicate the need to act against the high prevalences of osseous fragments in the limb joints of young Warmblood riding horses.

Estimation of genetic parameters for the prevalence of osseous fragments in limb joints of Hanoverian Warmblood horses

Genetic parameters were estimated for the prevalence of osseous fragments in distal (DIJ) and proximal interphalangeal (PIJ), fetlock (FJ) and hock joints (HJ) of Hanoverian Warmblood horses by using residual maximum likelihood (REML) with linear animal models. The analyses were based on the results of 10 standardized radiographs of all four limbs of 3725 young riding horses selected for sale at auction. Transformation factors onto the underlying liability scale were verified by a simulation study. The heritability estimates of osseous fragments on the liability scale were in the range of h2 = 0.19-0.60. Further analyses of osseous fragments in FJ and HJ were performed separately in males and females. In both sexes, the heritabilities of osseous fragments in HJ were higher (h2 = 0.41 in males, h2 = 0.25 in females) than those of osseous fragments in FJ (h2 = 0.21 in males, h2 = 0.23 in females). Osseous fragments in the phalangeal joints (DIJ, PIJ, FJ) were genetically correlated moderately positive (r(g) = 0.19-0.41). The genetic correlations between osseous fragments in the phalangeal joints and in HJ were negative (r(g) = -0.27 to -0.67). Particularly, this applied to osseous fragments in FJ in both sexes, to those in front FJ in males and to osseous fragments in front and hind FJ of females (up to r(g) = -1). The heritability of height at withers was estimated at h2 = 0.27-0.28. Genetic correlations between height at withers and osseous fragments in equine limb joints were mostly moderately positive (up to r(g) = 0.75). We conclude from our results that osseous fragments in phalangeal and hock joints are genetically different traits but sex-specific expression of osseous fragments was unlikely.

[Genetic analysis of the outcome of behavioural tests in puppies of the Hovawart breed]

The objective of the present study was to evaluate the importance of genetic and environmental sources of variation for results of puppy behavioural tests in the Hovawart dog. For these analyses test results of 5,608 puppies born in 1995 to 2000 have been used. Variance component estimation was performed for the traits contact, optical and acoustical influences, hunting affinity, appearance and temperament using multivariate linear animal models and Restricted Maximum Likelihood (REML). The models included test-year-season, sex, litter size, region of kennel, inbreeding coefficient of the animal and the test inspector as fixed effects. Additive genetic effects of the animal, permanent environmental effect of the litter and the effect of the kennel were considered as random factors. An extended model included the additive genetic maternal effect. The region of the kennel was significant for all traits and the most important factor among the fixed effects. The sex of the puppy was significant for the temperament. Test-year-season was significant for hunting affinity, whereas the test inspector was significant for optical and acoustical influences. The effects litter size and inbreeding coefficient of the animal did not influence any of the traits significantly. The estimated heritabilities for the traits of puppy behaviour tests ranged from h2 = 0.02 to h2 = 0.13 with standard errors of up to 0.03. Common environment of the puppies significantly influenced all behaviour tests and the estimates were between c2 = 0.13 and 0.22. The maternal heritabilities amounted up to h2 = 0.04. The additive genetic correlations between the traits were always highly positive (r(g) = 0.6 bis 1).

Genetic Evaluation of Elbow Angles as Predictors of Elbow Dysplasia in German Shepherd Dogs

Elbow angles were measured in X-rays of both elbows to elucidate the usefulness of such data for selecting against elbow dysplasia (ED) in German shepherd dogs. These measurements record the size, proportions and alignments of the anconeal process (PA), the radius (RA), the olecranon (OL), and the ulnar trochlear notch (UL). The reference system for evaluating the information content of the measurements was the score for ED (ED-SV) as recommended by the International Elbow Working Group. Data from 2645 X-rayed dogs born from 1998 to 2001 in 1331 kennels were analysed by using residual maximum likelihood procedures to estimate heritabilities, additive genetic correlations and residual correlations. The pedigree file included 11,426 dogs and contained ancestors for up to six generations. ED-SV was significantly influenced by sex, by age within sex and by month of birth. The elbow angles were significantly influenced by the month and year of birth, X-ray positioning of the dog's forelimbs, angle of elbow flection, litter size and number of dogs X-rayed by the veterinary practitioners. The following heritability estimates were found: h2=0.18+/-0.04 for ED; h2=0.76+/-0.04 for OL; h2=0.52+/-0.05 for PA; h2=0.50+/-0.04 for UL; and h2=0.39+/-0.04 for RA. The additive genetic correlations of ED-SV with three elbow angles (OL, UL and RA) were close to zero. A higher additive genetic correlation to ED-SV was found only for PA, for which r(g)=0.31. The distributions of predicted breeding values for susceptibility to ED were not affected by regarding the elbow angles as additional traits in the multivariate prediction procedure. Measurements of elbow angles were thus shown to be unsuitable for use in selection programmes against ED in German shepherd dogs.

Analysis of prevalence of presumed inherited eye diseases in Entlebucher Mountain Dogs

We analyzed the prevalence of the presumed inherited eye diseases (PIED) noncongenital cataract and progressive retinal atrophy in the Entlebucher Mountain Dog for systematic environmental influences and the additive genetic variation. Multivariate linear animal models using residual maximum likelihood methods and multivariate threshold animal models using Gibbs sampling in Bayesian analyses were used to estimate variance and covariance components. Data were obtained from the kennel club for Swiss Mountain Dog breeds in Germany. PIED were recorded using the standardized protocols of the Dortmunder Kreis, the German panel of the European Eye Scheme for Diagnosis of Inherited Eye Diseases in Animals (DOK). The material included 515 Entlebucher Mountain Dogs from 344 litters at 77 different kennels. Veterinary diagnoses for PIED were from the years 1981-2001. Pedigree information was available for up to nine generations. The multivariate animal model regarded the fixed effects of sex, birth year, experience of the veterinary ophthalmologist, litter size, percentage of examined dogs per litter, inbreeding coefficient and age at examination. The common environment of the litter and the additive genetic effect of the animal were taken into account as randomly distributed effects. The heritability estimates for PIED in the Entlebucher Mountain Dog were h2=0.15+/-0.06 (noncongenital cataract), and h2=0.34+/-0.08 (progressive retinal atrophy) in the linear model and h2=0.32+/-0.05 (noncongenital cataract) and h2=0.59+/-0.03 (progessive retinal atrophy) in the threshold model. The additive genetic correlation between noncongenital cataract and progressive retinal atrophy was moderately positive (r(g)=0.54+/-0.08) in the threshold model. The number of examinations performed by the veterinary ophthalmologists was associated with slightly higher heritabilities for noncongenital cataract and considerably higher heritabilities for progressive retinal atrophy. The investigated PIED in the Entlebucher Mountain Dog are genetically influenced and the size of the genetic parameters estimated may be sensitive to the accuracy of the diagnosis and how the data were collected.

[Survival analysis of German Holstein cows after an abomasal displacement]

From 1996 to 2002 5159 cattle with abomasal displacement was treated in the Clinic for Cattle, School of Veterinary Medicine Hannover. An analysis of systematic effects on influences on the length of survival following surgical correction of the abomasal displacement could be performed for 1411 cows. These animals were under the official milk recording scheme. Significant influences on lifetime after an abomasal displacement were interval between calving and diagnosis of disease, lactation number, type of abomasal displacement, inbreeding coefficient, calving difficulties, region of origin and sire of the calf. The lifetime after an abomasal displacement significantly differed between several months of calving and some sires of the cow. The individual milk yield in lactations before and after abomasal displacement of the cow was significant for the length of lifetime. The heritability estimate for length of lifetime after abomasal displacement using residual maximum likelihood (REML) in a linear animal model was h2 = 0.01-0.03.